In recent years, microchannel chips have been used to accurately and speedily analyze a trace substance such as protein and nucleic acid. Microchannel chips advantageously allow the amount of reagents or samples required for an analysis to be small, and are expected to be used for various uses such as laboratory tests, food tests, and environment tests. In view of this, microchannel chips of complicated structures and various shapes have been developed (see, for example, PTL 1).
The microchannel chip disclosed in PTL 1 includes four injection hole parts for injecting liquid, four micro channel inflow parts (hereinafter referred to also as “inflow parts”), a micro channel reaction tank part (hereinafter referred to also as “reaction tank part”), a micro channel separation part (hereinafter referred to also as “separation part”), and a waste liquid part. Each of the four injection hole parts, the reaction tank part and the waste liquid part is a bottomed hole formed in a substrate. Solid fine particles are disposed in the reaction tank part for a solid-phase reaction field. The four inflow parts are grooves formed on the substrate. One end of the inflow part is communicated with the reaction tank part, and the other end thereof is communicated with the corresponding one of the four injection hole parts. The separation part is also a groove formed on the substrate. One end of the separation part is communicated with a position facing the inflow part with the reaction tank part therebetween in the reaction tank part, and the other end thereof is communicated with the waste liquid part. Further, the cross-sectional area of the separation part channel is smaller than the diameter of the solid fine particle. With such a configuration, reaction materials introduced from the inflow parts to the reaction tank part are adsorbed on the solid fine particles, and the solid fine particles are blocked without flowing into the separation part. On the other hand, only unreacted materials introduced from the inflow parts to the reaction tank part are allowed to flow into the separation part, and are separated from the reaction tank part to the waste liquid part. In the microchannel chip, reaction materials of three types are introduced from the three inflow parts to the reaction tank part, and reaction is caused in the reaction tank part. After the reaction, the unreacted materials are separated from the separation part, and analysis is performed. It is to be noted that the remaining one inflow part can be used for introducing washing solution. As described above, in the microchannel chip disclosed in PTL 1, reaction materials of two or more types are introduced from two or more inflow parts to the reaction tank part to cause reaction and thus analysis can be performed as desired.
It is to be noted that, in the microchannel chip disclosed in PTL 1, a protection plate may be disposed on the surface of the substrate. The protection plate is provided with openings at positions corresponding to the four injection hole parts, the reaction tank part, and the waste liquid part, and thus the injection hole part, the reaction tank part and the waste liquid part are communicated with the outside. However, the openings of the inflow parts and the separation part which function as the channel are closed with the protection plate.